The present disclosure relates to systems and methods for delivering a graft material to a spine of a patient with reduced invasiveness. More particularly, the invention relates to a system and method including and utilizing a retractor and trocar configured for positioning a graft material along the spine of a patient with reduced invasiveness.
It is estimated that 8 out of 10 people will be affected by a spine condition during their lifetime, making potential treatment options like spinal fusion surgery an imperative area of surgical improvement. Spinal fusion is a surgical procedure focused on the fusion of two or more vertebrae along the spinal column for the purposes of immobilizing the vertebrae. Spinal fusion procedures can reduce back pain or facilitate the treatment of injuries including broken vertebrae, spinal deformities, spinal weakness, herniated back pain and chronic lower back pain.
In general, a spinal fusion procedure can include joining of two or more vertebrae together using surgical hardware and bone graft material. A typical surgery may include the insertion of both temporary stabilizing hardware and bone graft material. The stabilizing hardware can serve as a temporary solution for spinal stabilization. Specialized screws with heads having compressible clamps can be drilled into the pedicle on the dorsal side of the spine. A metal rod can then be threaded through the screw heads to connect all of the affected vertebrae. Due to the lack of biological integration with the bone, the hardware (e.g., screws, rods) can loosen over time, leading to mechanical failure. Therefore, a bone graft material can be positioned for the fusion of adjacent vertebrae to augment the hardware and contribute to maintaining long-term stability between the affected vertebrae within the spine. Bone graft can be placed in an anterior location between the vertebral bodies or a posterior location across bony elements (e.g. transverse process or lamina).
In the anterior interbody fusion method a graft is typically placed in between the vertebrae. The intervertebral discs are removed prior to decortication. However, this disc removal process can require a relatively lengthy (e.g., less than about 2 hour) surgery. Moreover the surgery can be highly invasive and risks causing injury to the nerves and or spinal fluid leak. The posterior fusion techniques are an alternative procedure which are comparatively less invasive can include the placement of bone graft on the decorticated posterior vertebrae surface lateral to the already implanted stability hardware. Spinal fusion may be induced on either the lamina or transverse processes. However lateral fusion procedures can still be relatively invasive in that a large incision and retraction of the skin and muscles can be required in order to place the bone graft. However, the depth to which the surgeon must cut is less than for intervertebral fusion.
In general, it can be useful to reduce both the length of time a surgery takes as well as the invasiveness of the procedure. So called “minimally invasive” techniques, which seek to perform the underlying procedure with a reduced amount of invasiveness when compared with traditional techniques, can put less stress on the body, minimize scarring, shorten hospital stays, lower healthcare costs, and greatly reduces pain. Statistics have shown that hospital stays are reduced by 60 percent or more as compared with conventional surgery. In addition, recovery from minimally invasive surgery can be faster with less discomfort experienced by the patient. Some of the benefits of minimally invasive procedures may be attributed to decreased blood loss, a lesser potential for injury to surrounding tissue, and a lower chance of infection since there is less exposure of tissue to the outside environment. Overall, a minimally invasive method for providing a posterior bone graft is unknown.
Currently, there exist minimally invasive methods for inserting the stabilizing hardware for spinal fusion percutaneously. The hardware is inserted by providing several small incisions through which to drill the screws into the affected vertebrae. An additional incision allows for the insertion and guidance of the metal rod. However, as the existing stability framework of screws and rods can begin to loosen over time (e.g., within about six to eight weeks), there remains a need to provide a graft material for long-term stability of the spine. Accordingly, there is a need for a system and methods for the implantation of bone graft material in a minimally invasive manner.